Residual current protective devices (RCDs) are protective devices in electrical systems and installations for protection against indirect contacts, i.e., electric contacts of people with exposed conductive parts that may have become live under fault conditions. RCD's may be required as protective measures in special areas of electrical systems and installations.
An RCD may operate based on the fact that the vector sum of all currents on the current-carrying conductors of a supply line is zero in the fault-free operation of an electrical installation and no induction is generated in a magnet core of the RCD. If because of an insulation fault a residual current occurs, which is discharged into a body or to ground outside of the supply line, a differential current is caused. A current is induced on the secondary side via the variable magnetic field of that differential current, said current triggering a power switch which separates the faulty supply line.
However, in case of a direct contact, i.e., the electric contact of the person with a conductor or a conductive part intended to be energized in normal operation an RCD or any common protective devices may not be capable of breaking the circuit with sufficient responsiveness to protect against electric shock or even electrocution of the person. Therefore there is a need in the art for an electrocution protection system that is capable of protecting a person in case of both direct and indirect electric contact.